JPS62244259A - Permanent magnet type motor - Google Patents

Abstract

PURPOSE:To improve the efficiency of a motor, and to inhibit torque fluctuation by mounting a permanent magnet, in which magnetic poles are skewed, while inclining the permanent magnet at values equal to the quantities of skews at the positions of splits and forming pole boundaries at the positions of splits. CONSTITUTION:An output shaft 1 is supported by a bearing 8, and holds a collar 9, a permanent magnet 5 and a magnet 3 for changing over phase, thus constituting a rotor. A coil 6 is wound on a stator core 4, and the stator core 4 is fixed to an end bracket 10. The permanent magnet 5 is constituted of split magnets 5a-5d, organized so that the positions of split are each used as pole boundaries, and inclined so as to coincide with the quantity of magnetizing skewing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a rotor structure of a permanent magnet motor having a rotor equipped with a permanent magnet.

[Conventional technology]

In order to suppress fluctuations in shaft torque (generally known as cogging torque) of permanent magnet electric motors, the magnetic poles of the rotor's permanent magnets are skewed (tilted) with respect to the poles of the stator stator coil. Yes 1 For example, 1987-
No. 53,679 also describes a permanent magnet type electric motor having the above-mentioned skew structure.

[Problem that the invention seeks to solve]

In a rotor with split magnets in the form of roof tiles.

By skewing the magnetic poles, fluctuations in shaft torque can be suppressed, but the magnetic flux density changes rapidly at the boundary between the divided stones, resulting in a problem of poor motor efficiency. An object of the present invention is to eliminate changes in magnetic flux density at boundaries between divided magnets, increase motor efficiency, and suppress torque fluctuations.

[Means for solving problems]

The above purpose is to split the split part of the roof tile-shaped split magnet.

This is achieved by tilting the magnetic pole parallel to the amount of skew, placing the skew in the divided part, and forming the boundary of the magnetic pole in this divided part.

[Effect]

A rotor formed of split magnets in the shape of roof tiles is generally formed by fixing several pieces at a time to a rotating shaft with an adhesive. Since a gap is always created at the division boundary, the magnetic flux density at this portion is reduced. Conventionally, a skewless motor has a structure in which the magnetic poles are formed such that this portion becomes the magnetic pole boundary. In a split magnet with skewed magnetic poles,
Although a decrease in magnetic flux density due to the gap at the dividing boundary cannot be avoided, by slanting one dividing boundary parallel to the skew amount and forming a magnetic pole boundary at this dividing boundary as in the conventional structure, the dividing boundary can be reduced. The decrease in magnetic flux density at the end of the motor is reduced or eliminated, increasing motor efficiency and suppressing torque fluctuations.

〔Example〕

An embodiment of the present invention is shown in FIGS. 1 to 4 below.

Fig. 1 is a half-sectional view showing the structure of the permanent magnet type electric motor of the present invention, Fig. 2 is a perspective view of the rotor section showing the structure in which the permanent magnets shown in Fig. Developed view showing the arrangement of divided magnets of the rotor and one-turn cylinder II on the surface of rotor central part A
(360"), in which (a) is a developed view, (b) is a magnetic flux density waveform diagram, and Figure 4 is a perspective view showing the shape of a one-divided magnet. In Figure 1, the output shaft 1 is supported by a bearing 8, and includes a collar 9, a permanent magnet 5,
It holds the phase switching magnet 3 and constitutes a rotor. A coil 6 is wound around the stator core 4, and the stator core 4 is fixed to an end bracket 10. 2 corresponds to the phase switching magnet 3, and a Hall element 27 fixed to the end bracket 10 is a frame, which is combined to form a stator. The Hall element 2 is used to detect the position of the coil 6 in order to regularly energize it. FIG. 2 is a diagram showing the structure of the rotor section of FIG. 1.

Then, the divided magnets 5a*, 5b*, 5c, and 5d are fixed to the collar 9 with adhesive, and the divided magnets 5a*, 5b*, 5c, and 5d are placed at the dividing position.

Figure 3 (a) shows a developed six-rotor structure in which O and ■ are configured to be magnetic pole boundaries, respectively, and are tilted to match the magnetization skew amount θ. Also, the surface magnetic flux distribution waveform of the central part A of the rotor is shown in Figure 3 (b), which shows that the magnetic flux density drops at the split position when the skew amount θ is set, which has been a problem in the past. There is no change in density at the positions ■', ■', ○', and ■' in FIGS. 6, (c) and (d). FIG. 4 is a perspective view showing the shape of one divided magnet of the divided magnet 5d in FIG.
* The conventional rotor structure is shown in FIGS. 5 to 7, which show that the O end face is inclined to match the magnetic pole skew amount θ, and a magnetic pole boundary is formed at this portion. FIG. 5 is a perspective view of the rotor showing that the divided magnets 5a', 5b', 5c', and 5d' are magnetized so as to form the magnetic pole skew amount θ. is the 1 division position. When the structure of this rotor is developed and shown, it is shown in Fig. 6(c). Fig. 6(d) is a magnetic flux distribution waveform diagram at part B of the rotor's central surface. At 0' and 2', the magnetic flux drops, which causes a decrease in the efficiency of the motor.

FIG. 7 is a perspective view showing the shape of one divided magnet of the divided magnet 5d' in FIG. form 1
According to the present invention, the shaft torque fluctuation near the skew amount θ is reduced by tilting the split magnets at the split position so as to match the magnetization skew amount of 0 and forming the boundaries of the magnetized magnetic poles at this portion. , it is possible to stabilize the magnetic flux density waveform and obtain an efficient permanent magnet motor.

〔Effect of the invention〕

As described above, according to the present invention, even if the magnetic pole skew amount θ is formed in the one-segment magnet, it is possible to suppress the shaft torque fluctuation, and moreover, it is possible to eliminate the drop in magnetic flux density at the split position. , which has the effect of improving the efficiency of the electric motor.

[Brief explanation of drawings]

FIG. 1 is a half-sectional view of a permanent magnet type electric motor showing one embodiment of the present invention, FIG. 2 is a perspective view showing the structure of its rotor, and FIG.
The figure shows the relationship between the developed state of the rotor magnets in Fig. 2 and the magnetic flux density distribution diagram on the surface of the rotor central part A, Fig. 4 is a perspective view of one divided magnet, and Fig. 5 shows the conventional rotor structure. Perspective view, No. 6
The figure shows the relationship between the developed state of the rotor magnets in FIG. 5 and the magnetic east density distribution on the surface of the rotor central portion 8, and FIG. 7 is a perspective view of one conventional divided magnet. 1... Output shaft, 2... Hall element, 3... Phase switching magnet. 4... Stator core, 5... Permanent magnet, 5a...
Divided magnet, 5b...Divided magnet, 5c...Divided magnet,
5d...Divided magnet, 5a'...Divided magnet, 5b'.
... Divided magnet, 5c'... Divided magnet, 5d'... Divided magnet, 6... Coil, 7... Frame, 8...
Bearing, 9...Color, 10...Engineering plastic, A...
Center part of rotor surface, B... Center part of rotor surface, ■...
・Divide position, ■...Divide position, ■...Divide position, ■・
・・Division position, ■・・・・Division position, ■′・・・・・Division position, ■′・・・・Split position, ■−・・・Split position, 0・・Skew angle, N1・・Magnetic pole, NZ・...Magnetic pole, St.
...Magnetic pole, Sz...Magnetic pole, (,)...Development view, (b)
...Magnetic flux density distribution diagram, (c)...Development diagram, (d)
...Magnetic flux density distribution map.

Claims (1)

[Claims] 1. A stator core around which a winding is wound, a frame to which this stator core is fixed, a bearing placed on one or both sides of this frame, a rotating shaft rotatably supported by this bearing, and this rotation. In a rotor that is fixed to a shaft and has a rotor with permanent magnets as magnetic poles, permanent magnets with skewed magnetic poles are provided, and the permanent magnets are tilted at divided positions equal to the skew amount, and the magnetic poles are installed at the divided positions. A permanent magnet electric motor characterized by forming a boundary.